1. Field of the Invention
The present invention relates to a magneto-resistive (MR) head provided with an MR element, and in particular, to an MR head that runs in contact with a magnetic medium and a method for producing the same. The present invention also relates to a magnetic recording/reproducing apparatus using the MR head.
2. Description of the Related Art
In recent years, to increase the density of magnetic recording, attention has been given to producing a magnetic head using a thin film technique. In particular, an MR head is being studied as a head of a rotating drum type VTR and the like (for example, IEEE TRANSACTIONS ON MAGNETICS, Vol. 34, No. 4, July 1998 (SONY)).
FIGS. 10 and 11 respectively show a perspective view and a cross-sectional view of a typical configuration of an MR head (yoke type). The MR head comes into contact with a recording medium, such as a magnetic tape and a magnetic disk, on a side face 10 on the left side of the figure. A magnetic flux generated from the recording medium is guided from a lower magnetic yoke 11 to an upper rear magnetic yoke 13, an MR element 14, and an upper front magnetic yoke 15, and a change in resistance caused by magnetization rotation of the MR element 14 is taken out from an output terminal 16. The MR head further is provided with a magnetic gap 18, a bias layer 19, a protective film 20, a lower substrate 21, an upper substrate 22, and an adhesive film 23. In order to show an internal configuration, in FIG. 10, the protective film 20, the adhesive film 23, and the upper substrate 22 are not shown.
An MR element portion 30 is formed by a thin film formation technique, so that it is weak in terms of strength unlike a bulk material. Therefore, the element portion is interposed between the lower substrate 21 and the upper substrate (reinforcing body) 22. In order to bond the MR element portion 30 to such a substrate, the adhesive film 23 is provided at least on one side of the MR element portion 30. As the adhesive film 23, an organic adhesive is used.
However, when the MR head is allowed to slide over the recording medium, a component of the recording medium adheres to the adhesive film 23 exposed to a sliding surface between the MR head and the recording medium. On the other hand, a component of the adhesive film also adheres to the recording medium. Because of these adhesions, both the MR head and the recording medium are likely to be damaged.
Furthermore, due to the difference in material between the adhesive film 23, and the lower substrate 21 and the upper substrate (reinforcing body) 22, as the MR head runs in sliding contact with the recording medium, recession (biased abrasion) becomes more likely to occur in the MR head. When the gap occurs between the MR head and the recording medium because of the recession on the sliding surface, a spacing loss degrades reproduction characteristics.
The present invention provides an MR head that is capable of suppressing a decrease in reliability even when it slides over a magnetic recording medium, and a method for producing the same. The present invention also provides a magnetic recording/reproducing apparatus using the MR head.
According to the present invention, in an MR head including a substrate, an MR element portion formed on the substrate, a reinforcing body, and a sliding surface with respect to a magnetic recording medium, the substrate and the MR element portion being exposed to the sliding surface, the substrate and the reinforcing body are bonded to each other in such a manner that an organic film is not exposed to the sliding surface with respect to the magnetic recording medium.
In one embodiment of the MR head according to the present invention, the substrate and the reinforcing body are bonded to each other via a non-organic film.
In another embodiment of the MR head according to the present invention, the substrate and the reinforcing body are bonded to each other via an adhesive film that is not exposed to the sliding surface with respect to the magnetic recording medium. The adhesive film may be an organic film or a non-organic film. However, it is preferable that the adhesive film is not formed in a range of 5 xcexcm from the sliding surface along an interface between the substrate and the reinforcing body.
Furthermore, according to the present invention, an MR head including a substrate, an MR element portion formed on the substrate, a reinforcing body, and a sliding surface with respect to a magnetic recording medium, in which the substrate and the MR element portion are exposed to the sliding surface, is produced by a method including the acts of: forming an MR element portion on a surface of a substrate; forming a flat surface above the MR element portion; forming non-organic films each including metal layers respectively on the flat surface and the surface of the reinforcing body; and subjecting the metal layers to solid-phase welding, thereby bonding the substrate and the reinforcing body to each other.
Furthermore, according to the present invention, a magnetic recording/reproducing apparatus including the above-mentioned MR head and a magnetic recording/reproducing apparatus including the MR head produced by the above-mentioned method are provided.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.